The effective combination of data processing techniques with telephonic communication has greatly expanded the volume of telephonic digital communication. For example, a considerable volume of such traffic involves inquiries to central-computer data stations from which various information may be obtained. Specifically, for example, digital-data inquiries to data banks relating to the status of credit cards are commonplace. By conventional practice, pertinent identification information is sensed from a credit card at remote terminals to formulate digital signals constituting an inquiry to a central data station. Such signals are telephonically communicated to the central data station where relative information on the subject of inquiry is located and returned to the inquiring terminal. A display at the terminal may be used to advise the approval or dissapproval of a transaction under consideration. Thus, an operator at an inquiry terminal simply passes a credit card through a reading mechanism and seconds later he is able to view a display showing the status of a card tendered to support a contemplated transaction.
With the widespread use of telephonic inquiry systems, telephone economics have become exceedingly important, particularly where inquiry terminals are separated from a central data bank by a considerable distance. In that regard, consider credit inquiries to a remote data station from a large commercial facility, for example, a major metropolitan hotel. Such an establishment may have many telephone terminals from which credit card inquiries can be initiated. During peak business hours, several credit card inquiries may occur almost simultaneously from different terminals within the hotel. In the space of minutes inquiries might originate from different cashier stalls, restaurant facilities, bar facilities, transportation facilities and so on. In accordance with the conventional practice, each inquiry would involve a separate dialing operation, a separate dial-up and separate attendant charges.
Accommodating the economics of telephonic communication, charges for individual calls normally include a minimum. For example, long-distance calls routinely involve a minimum charge that is incurred on establishing communication between connected stations. Afterwards, a time-related rate is applicable. Such charge schedules, reflecting the economics of telecommunication, result in the cost of several separate calls being much higher than the charge if the same communications were accomplished during a single dial-up call. Accordingly, with respect to digital telephonic inquiries, substantial economy can result from concentrating multiple inquiries into a single call to result in a single dial-up charge. In general, the present invention involves recognizing the need for a system with such capability and developing the resulting system in accordance with available telecommunications.
In accordance with the present invention, several telephone inquiry terminals are integrated as a cluster. Normally the cluster will consist of telephones at a facility, each with access to a common extension line. Implementing the cluster is a transmit-receive unit, normally located remote from the cluster. The transmit-receive unit also interfaces a central data station in the system. Accordingly, the system may reduce the number of telephone lines, save time for inquiries through the cluster and reduce the number of calls for more economical operation.
To initiate an operating sequence within a cluster in accordance with the present invention, one of the telephone terminals may be actuated (taken "off-hook") to command dial-up and the resulting operation of the cluster system. Thereafter, in a continuing operation, the line remains "off-hook" to preserve the connection until all communication is complete. Then terminals assume a "listening" or standby mode. Accordingly, a polling format is established to accommodate transmission of multiple inquiries and responses from and to the individual terminals. The system facilitates such continued operation until all terminals are quiescent. The telephone line then is relinquished (going "on-hook") terminating the call.
As disclosed in detail below, the system hereof may be variously implemented using different signal formats, different data processing structures and different techniques. For example, various programming and polling techniques may be employed. Also, various forms of telephone sets, data readers, displays and registers may be incorporated in systems in accordance herewith.